Nobody knows more about global inequality than Branko Milanovic. If he doesn't know it, it's probably not worth knowing. His book Global Inequality is probably the best entry point into his work but all his books are good and there are a zillion of his papers available on the web.
That said, there's no denying that his close reading of the empirical record is not to everyone's taste. Perhaps you don't want to slog through his collected works. No problem! I strongly recommend this piece he put on this blog--a "non-technical" summary of what we know about global inequality. Read it and, lo, you will be wiser!